Rupert Murdoch and his sons, who run the company, are attempting to clean up the firm after a series of embarrassing revelations: Getty

Discrimination and intimidation of employees at Rupert Murdoch’s Fox News makes parent company 21st Century Fox unsuitable to launch a full takeover of Sky, a lawyer representing alleged victims has claimed.

Douglas Wigdor, a New York-based solicitor acting on behalf of 19 current and former employees of the media giant, has written to Ofcom in a bid to derail Mr Murdoch’s £11.7bn attempted takeover of the British broadcaster.

The 36-page letter alleging sexism and racism at Fox was sent to the regulator’s chief executive, Sharon White, on Wednesday.

It details allegations of “gender and race discrimination, harassment, and retaliation” at Fox that are said to stretch back more than eight years.

The document, seen by The Independent, accuses the company of attempting to “intimidate and silence victims of discrimination and force them to litigate their claims in confidential arbitrations in order to prevent the public from learning about its unlawful conduct”.

It says Fox has employed “attorneys who are so willing to bring meritless retaliatory actions against employees who allege discrimination in order to intimidate those employees and silence their allegations”.

The letter continues: “This practice, in addition to requiring many employees to sign arbitration clauses to prevent them from publicly disclosing Fox’s unlawful conduct, undercut any claim that Fox’s Corporate Governance has any real interest in resolving its internal problems.

“It also bears noting that Fox has reportedly used various means to attempt to conceal and cover up other misconduct.”

In the letter, Mr Wigdor also asks to meet with Ms White to discuss his concerns.

Douglas Wigdor raises his hands as he addresses the media with Fox News host Kelly Wright (L), one of those involved in the race discrimination class-action lawsuit (Reuters)

The timing of the intervention is significant as the media regulator is due to deliver its verdict on the controversial takeover bid next month.

Ofcom has been conducting a review into whether Fox is "fit and proper" to buy the remaining 61 per cent of shares in Sky, with its report due to be published on 20 June.

A spokesman for the regulator confirmed to The Independent it had received the letter and would consider it as part of the review into 21st Century Fox's plans to gain full ownership of the broadcaster, but refused to comment further on the details of the letter or Ofcom’s review.

Claims made against him by former Fox & Friends co-host Gretchen Carlson said that he “ogled” her and suggested they engage in a sexual relationship.

Mr Ailes dismissed the accusations as a “retaliatory suit for the network’s decision not to renew her contract, which was due to the fact that her disappointingly low ratings were dragging down the afternoon lineup”.

In an email to staff, 21st Century Fox said: “After a thorough review of the allegations against him, the company and Bill O’Reilly have agreed that Mr O’Reilly will not return to the Fox News Channel."

Mr Murdoch’s bid to seize control of Sky suffered a further knock this week when a cross-party group of influential MPs met with Ofcom executives to voice their opposition to the takeover attempt.

Tuesday’s meeting involved former business secretary Vince Cable, former Labour leader Ed Miliband and former chancellor Ken Clarke, who argued that governance failures and a lack of transparency at 21st Century Fox made it unsuitable to take full control of Sky.

They warned in a letter to Ofcom that there was "clear evidence of the Murdochs' pattern of secrecy and lack of transparency about corporate failure being repeated at Fox News, the subject of ongoing Federal investigations”.

The takeover deal has already been cleared by EU regulators but Ofcom and the Competition and Markets Authority (CMA) have yet to publish their judgments.

Once those verdicts have been given, the Culture Secretary Karen Bradley will have 10 working days to approve it or ask for a more detailed report.

In 2011, Mr Murdoch tried and failed to take over Sky under the News Corporation umbrella.

He faced strong opposition from industry rivals and MPs and was forced to drop the bid following pressure on the company in the wake of phone-hacking claims involving News International.

A representative for 21st Century Fox said the company "has taken prompt and decisive action to address allegations of sexual harassment and workplace issues at Fox News".